<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        /* border-width  border-style border-color */
        /* border: 1px solid; */
        width: 600px;
        margin: 50px auto 0;
      }

      .box span {
        border: 1px solid;
        /* display: inline-block;
        width: 100px;
        height: 40px; */
        line-height: 40px;
        text-align: center;
        padding: 10px;
      }
      .box span:hover {
        color: #ff6700;
        cursor: pointer;
      }
      .box .content {
        position: absolute;
        left: 0;
        z-index: 9999;
        width: 98%;
        height: 0;
        background-color: #ccc;
        overflow: hidden;
      }

      .box span:hover + .content,
      .content:hover {
        height: 200px;
        animation: show 0.5s ease-out 0s 1;
      }

      @keyframes show {
        from {
          height: 0;
        }
        to {
          height: 200px;
        }
      }

      section {
        display: flex;
      }
    </style>
  </head>
  <body>
    <section>
      <div class="box">
        <span>小米手机 </span>
        <div class="content">
          手机 手机
          <img src="../other/butterfly.png" alt="" />
        </div>
      </div>
      <div class="box">
        <span>电脑 </span>
        <div class="content">电脑</div>
      </div>
    </section>
  </body>
</html>
